In torque transferring systems that involve a torque transferring device it is important to be able to determine a condition of the torque transferring device. A torque transferring device may e.g. be a power tool such as a nutrunner, or a transmission apparatus, such as a gear box. It is, for example important to be able to determine a condition of the meshing gears included in the torque transferring device. Such meshing gears include spiral bevel gears, consisting of a crown gear and a pinion gear, fixed ring gears, sun gears, planet gears, and essentially any other gears that are used for transferring the torque through the system.
In this document, the invention will be described mainly for its implementation in a tool, such as a nutrunner. However, the invention is generally applicable to essentially any other torque transferring system.
A nutrunner provides a torque to a nut in order to tighten or loosen the nut. The nutrunner includes meshing gears. The purpose of these gears is mainly to increase the amount of torque that can be provided to the nut by the nutrunner, which is achieved by gearing down the rotation motor of the nutrunner by means of said gears. The gears may also serve as angle gears to change the axis of rotation of the torque. The angular rotational speed that is provided by a motor in the nutrunner is geared down by the meshing gears to a degree that corresponds to the relation of the number of cogs on the meshing gears, whereby the torque applied to the nut is increased to a corresponding degree at the same time as the rotational speed is decreased to the same degree.
Hence, the meshing gears are a vital part of such a torque transferring devices, and it is important that their condition is good.
Torque transferring devices, such as tools, are widely used in e.g. manufacturing and repair processes. Such manufacturing or repair processes rely on the well function of the tools for securing a continuous manufacturing or repairing. In order to avoid manufacturing or repairing pauses, that are both annoying and expensive for the manufacturer or repairer, it is important to be aware of the condition of the tools that are used in the manufacture or repair process.
In known solutions to this problem, the tools are taken out of use, e.g. out of the manufacturing or repairing process, and are analyzed under controlled conditions in an external analysis apparatus for tool condition determination. Thus, an external apparatus is needed for performing this analysis, which of course adds on to the manufacturing or repairing costs.
Also, since the tools have to be taken out of use when they are analyzed, the manufacturing or repairing process has to be stalled during the analysis, or there has to be an abundance of tools present at the manufacturing or repairing site, such that a replacement tool could be put to work when the analysis is performed.
Both stalling of the manufacturing or repairing and purchasing of replacement tools add to the production or maintenance costs for the items that are being produced or repaired. Since cost is a crucial competition factor in manufacturing and repairing processes, it is important to minimize the costs involved in tool condition control.